mispronounce is the correct word. "It also happens with beer, bill, and veal" sounds more natural because the confusion could come from beer and bill or bill and veal or beer and veal. For the first sentance "I know someone who received the wrong items while ordering because they pronounced the words incorrectly." sounds more natural.

There are some English words ( or a few ) that Japanese people ( or natives ) find difficult to pronounce . They often mispronounce Bill (as in a sheet of paper), as veal (as in the type of cow).
* Although Japanese and Chinese and even Korean all mean both language and people from that country, you always must specify if it's the language or people from that country. People may not be sure if you're talking about 日本人 or 日本語.